A high-throughput protocol for deriving microglia from human stem cells

Scientists from the New York Stem Cell Foundation (NYSCF) Research Institute have developed a robust, efficient method for deriving microglia, the immune cells of the brain, from human stem cells. Microglia are increasingly implicated in neurological disorders including Alzheimer's disease, Parkinson's disease and multiple sclerosis, among many others. However, research into the role of human microglia in these disorders has long been hampered by the inability to obtain them from the human nervous system. This new protocol now enables scientists around the world to generate this critical cell type from individual patients and improve our understanding of the role of microglia neurological malfunction.

Published in Stem Cell Reports, this microglia protocol is optimized for use in high-throughput experiments, such as drug screening and toxicity testing among other large-scale research applications, and has the benefit of allowing such experiments to be carried out on multiple patient samples. The scientists determined that the protocol is robust and reproducible, generating microglia from sixteen induced pluripotent stem (iPS) cell lines, stem cells that are created from individual patients.

Myeloid progenitors expressing CD14/CX3CR1 were generated within 30 days of differentiation from both embryonic and induced pluripotent stem cells (iPSCs). Further differentiation of the progenitors resulted in ramified microglia with highly motile processes, expressing typical microglial markers.

Analyses of gene expression and cytokine release showed close similarities between iPSC-derived (iPSC-MG) and human primary microglia as well as clear distinctions from macrophages. iPSC-MG were able to phagocytose and responded to ADP by producing intracellular Ca2+ transients, whereas macrophages lacked such response.

Microglia from humans have long been a desired research model, but are difficult to obtain for laboratory experiments. The NYSCF protocol provides a new source of human microglia cells, which can be generated from disease patient samples and will complement studies in mouse models to better understand the role of microglia in health and disease. Microglia generated by the NYSCF protocol will thus provide a critical tool to investigate microglia dysfunction in central nervous system disorders and advance complex disease modeling in a dish.